Raphael josia



Urvrren STATES ATENT Fries.

RAPHAEL JOSIA, OF FLORENCE, ITALY, ASSIGNOR TO WILLIAM REY AND C. DE VARIGNY, BOTH OF PARIS, FRANCE.

COMPOSITION FOR TREATING SULPHATES OF LIME FOR THE MANUFACTURE OF ARTIFICIAL MARBLE.

SPECIFICATION formingpart of Letters Patent No. 265,503, dated October 3, 1882.

Application filed August 9, 1882. (No specimens.)

To all whom it may concern:

Be it known that I, RAPHAEL JOSIA, of Florence, Kingdom of Italy, have invented or dis covered a new and useful Improvement in Compositions for Treating Sulphates of Lime for the Manufacture of Artificial Marble; and I do hereby declare the following to be a full, clear, concise, and exact description thereof.

In an application for Letters Patent of the United States filed March 2, 1882, I have described and made claim to an improved process of treating or preparing gypsum (calcic sulphate or sulphate of lime) in the making of articles of a material which I have termed certaldite, without pulverization of the gypsum. In said application I described briefly certain of the compounds or compositions which I employ to produce certain effects and the manner of using them, but stated that separate appli- 2o cations would he made for patents for such compositions.

The present application relates to one of the compositions so referred to, and it is designed for use in the process herein described in the making of certaldite of rose or pink color or tinge.

1n carrying out the process referred to a suitable piece of gypsum (calcic sulphate) is first formed into the desired shape, or approximate- 0 1y such, by the use of suitable well-known tools.

The gypsum employed maybe the ordinary native gypsum of commerce, though I prefer that which is comparatively pure or tree from other matters of different composition. Such gyp- 5 sum is usually obtained hydrated, or containing a certain percentage of water in its composition; and the second step in the operation has reference to depriving the gypsum under treatment of a considerable part or the whole of such water. This is done by subjecting it to the action of a gradually-increasing heat, varying by preference with the size and quality of the material from 260 to 300 Fahrenheit, for about twelve hours, or until the de- 5 sired partial or complete dehydration is obtained. The length of time as well as the degree of heat required to effect this result will varysomewhat with the size,character, and purity of the gypsum employed; but the tempera- 5o ture should not exceed 500 Fahrenheit, and

both itand the time of exposure should be regulated and limited with reference to securing uniformity of treatment throughout the whole mass or body. This operation may be known to be complete when a fracture of a test block presents a uniform white color. Any suitable drying or baking apparatus may be employed for this purpose, many such being known in kindred branches of the arts; but it should be of such construction that the material under treatment shall not be brought into direct contact with the fire. \Vhen the desired dehydration has been effected the furnace is allowed to cool gradually, in order that the material under treatment may be. cooled gradually; or the material may be removed with due care to prevent breaking and exposure to moisture,

and allowed to cool outside the furnace gradually until it is reduced in temperature sufficiently to permit handling with safety in its subsequent treatment, which is designed to impart to it the desired color or tint and a high degree of insolubility and hardness throughout its mass. This step involves the use of the composition which forms the subject-matter of invention in the present application. This composition is formed of the following elements: water, by weight, two hundred parts; alum, by weight, four to five parts; oxalic acid, by weight, two to two and a halt parts; rose of aniline, by weight, one one-hundredth to two one-hundredths parts. These ingredients, being mixed in about the proportions named, form a solution which is used as a bath, and to this enda suitable quantity of it is placed in a vessel of proper shape to receive the article to be treated, which is dipped or immersed in the bath and subjected to its action until the article has acquired the desired degree of hardness and color. The length of time required to effect this result will depend somewhat on the strength of the ingredients composing the bath or solution, the porosity and nature or physical and chemical condition of the article; but usually twelve hours (more or less) will suffice, though to secure uniformity of treatment and of result through the whole body or mass of the article I prefer repeated dippingstwo, three, or more-say two or three seconds at first, and increasing gradually to one, two, or three or more minutes, more'or less, with drying intervals of like increasing length besubstitute for marbles and ornamental stones,

tween dippings, for halfor three-quarters of an hour or so, after which the article may remain in the bath for twelve hours or so.

\Vhile I do not limit my invention by any particular theory of chemical or physical reactions involved in the use of this bath as above described, I believe, with my present knowledge, that the salt (alum) held in solution, by taking the place of the molecules of water dis= placed by the previous dehydrating operation, acts chemically or physically upon the calcie sulphate, and renders it more compact, harder, and less soluble, and that the oxalic acid of the bath acts chemically or physically upon the impurities or matters of other com position, (carbonates, &c.,) which are usually contained in greater or less quantitiesin native gypsums, and prod uces a li keinduratingeflect upon them, though the salt may also have an indurating action upon the impurities present, and the acid may act in like manner more orless upon the calcic sulphate. Therese of anilinein the bath acts as a coloring agent, and by varying the proportion employed, as above indicated, it imparts to the article under treatment a rose, I0tl(llSll,Ol pink color or tinge or tint, not alone upon its surface, but diffused through its mass, though lines, veins, and markings of darker shades will usually appear, which are due probably to the impurities present in the calcicsulphate. Highly-ornamentaland beau tifully-variegated colors are thus secured, as well as such a degreeot hardness, density, and insolubility as renders the article an excellent tiles, and other materials of kindred naturein the various uses to which they are applied in the arts.

When the article has been treated in the bath as above described it is removed and dried by exposure to the sun orto an equivalent furnace-heat for one or two hours, or by ordinary atmospheric exposure for two or three days, when it is ready for polishing and such other manipulation as may best fit it foritsintended use, which may be done by any of the methods practiced in kindred arts.

No claim is made herein to the process set forth, as that, with various modifications ofthe same, as circumstances may require,forms the subject-matter of the first application herein referred to. Neither do I limit my presentinvention to the particular way herein described of applying it, though I now believe this way or process to be the best. I also believe the proportions ofingredients which 1 have named in forming my improved composition to be the best for the purposes stated, and, among others, to secure a uniform degree of hardness and color throughout the mass of the article. It the solution be very strong, there is great danger of rendering the surface of the article hard very quickly, and thereby preventing proper action of the bath upon the interior substance ofthe article; or itthe solution be very weak too much time is required,and even thenaproper degree of hardness, density. and insolnbility is not secured; also, by the conjoint action of all the elements of the bath much better results are secured, especially upon native gypsums, than by a solution formed of a part of the elements. For these reasons I prefer to employ all the elements of the composition in substantially the proportions named; but such limits, though the best, may be varied somewhat and still attain good results under skillful manipulation, and all such modifications which employ the elements substantially as herein described and in about the proportions set forth I consider as coming within my invention and claim.

I claim herein as my invention- The composition herein described for treating dehydrated gypsum, consisting substantially ot the following elements: water, alum, oxalic acid, and rose of aniline, in about the proportions set forth.

In testimony whereofI have hereunto set my hand.

RAPHAEL JOSIA. 

